Troubleshooting & Repair

Control Techniques UNIDRIVE Alarm and Status Indications

Control Techniques Unidrives

When there is a critical condition detected in your Control Techniques UNIDRIVE, the drive will continue to operate, but the lower display’s status indication will be replaced by an alarm indication. When an HF trip takes place, the Drive Healthy relay will open and serial communications will not function. It is important to give attention to alarm indications, because if an issue is not corrected, the drive could trip.

Refer to the guide below to help identify what kind of error your UNIDRIVE may be experiencing. A comparison chart with status indications is also provided to help identify what happens at each stage of operation.


Alarm Code Alarm Description
AIR Control PCB ambient temperature near maximum limit
The ambient temperature around the control PCB has reached 90 degrees Celsius (194 degrees Fahrenheit). If the temperature continues to rise, the drive will trip OA.
br.rS Braking resistor is overloaded
The braking resistor [l x t] accumulator in the drive has reached 75% of the value at which the drive will be tripped.
Hot Heatsink temperature near maximum limit
The heatsink in the drive has reached 90 degree Celsius (194 degree Fahrenheit). If the temperature continues to rise, the drive will trip Oh2.
OVLd Motor is overloaded
The motor [l x t] accumulator in the drive has reached 75% of the value at which the drive will be tripped.

Status Indications of the Drive

These indications are seen in the lower display when the drive is in normal operation.

LOWER DISPLAY DESCRIPTION STAGE OF DRIVE OUTPUT
Act Regeneration Mode is active ENABLED
Regen drive enabled and synchronized to the supply
ACUU AC Supply Loss ENABLED
Drive has detected that the AC supply has been lost and is decelerating the motor to maintain the DC bus voltage.
dc DC has been applied to the motor ENABLED
Drive is applying DC injection braking
dEC Deceleration ENABLED
Drive is decelerating the motor
inh Inhibit DISABLED
Drive has been inhibited and cannot be run. Could be because the Drive Enable signal is not applied to terminal 30 or Pr 6.15 is set to 0.
POS Positioning ENABLED
Drive is positioning the motor shaft
rdY Ready DISABLED
Drive is ready to be run
run Running ENABLED
Drive is running
SCAn Scanning ENABLED
OL> Drive is searching for the motor frequency when synchronizing to a spinning motor.
Regen> Drive is enabled and synchronizing to the line.
StoP Stop or holding zero speed ENABLED
Drive is holding the motor at zero speed.
Regen> Drive is enabled but the AC voltage is too low or DC Bus voltage is still rising or falling.
triP TripCondition DISABLED
Drive has tripped and no longer controlling the motor. Trip code appears on upper display.
Joe Kaminski

Joe Kaminski is an industrial automation specialist at MRO Electric. He has a background in industrial engineering and supply chain management. Joe has worked in the automation industry for over 10 years providing support to some of the largest companies in the world. For more info, visit www.mroelectric.com.

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Joe Kaminski

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